Transcatheter mitral valve repair: review of current techniques

Combined Significant Aortic Stenosis and Mitral Regurgitation: Challenges in Timing and Type of Intervention

In this narrative review, we aim to summarize the literature surrounding the assessment and management of the common, yet understudied combination of aortic stenosis (AS) and mitral regurgitation (MR), the components of which are complexly inter-related and interdependent from diagnostic, prognostic, and therapeutic perspectives. The hemodynamic interdependency of AS and MR confounds the assessment of the severity of each valve disease, thus underscoring the importance of a multimodal approach integrating valvular and extravalvular indicators of severity. A large body of literature suggests that baseline MR is associated with reduced survival post aortic valve (AV) intervention and that regression of MR post-AV intervention confers a mortality benefit. Functional MR is more likely to regress after AV intervention than primary MR. The respective natural courses of the 2 valve diseases are not synchronized; therefore, significant AS and MR at or above the respective threshold for intervention might not coincide. Surgery is primarily a 1-stop-shop procedure because of a considerable perioperative risk of repeat interventions, whereas transcatheter treatment modalities allow for a more tailored timing of intervention with reassessment of concomitant MR after AV replacement and a potential staged intervention in the absence of MR regression. In summary, AS and MR, when combined, are interlaced into a complex hemodynamic, diagnostic, and prognostic synergy, with important therapeutic implications. Contemporary approaches should consider stepwise intervention by exploiting the advantage of transcatheter options. However, evidence is needed to demonstrate the efficacy of different timing and therapeutic options.

Circumflex Coronary Artery Injury during Modern Mitral Valve Surgery-A Review of Current Concepts and Perspectives

The devastating impact of a circumflex coronary artery (CX) injury during mitral valve (MV) surgery is well reported. Despite significant improvements in preoperative risk assessment, intraoperative diagnosis and perioperative treatment strategies of CX injury during MV surgery, recent reports re-emphasize the variability in presentation, the unpredictable mechanisms of injury and the conflicting evidence regarding perioperative management. The progressive transition from conventional sternotomy access to minimally invasive surgical and transcatheter (TC) interventions for MV disease are associated with significant learning curves and require additional single-shaft and robotic console suture manipulation skills with special attentiveness to the potential risk of CX injury. The introduction of hybrid theatres that facilitate single stage surgical and TC interventions also provides new intraoperative diagnostic and therapeutic options without transporting unstable patients for percutaneous coronary intervention (PCI) assessment. By utilizing a MeSH terms-based PubMed search, a total of 89 patients with CX injury that occurred during MV surgery was identified from 49 reports between 1967 and 2022. MV surgery was performed by conventional sternotomy (n = 76, 85.4%), endoscopic (n = 12, 13.4%) and robotic access (n = 1, 1.1%), with 35 injuries (39.3%) resulting in total CX occlusion. Rescue PCI was utilized in 40 patients (44.9%). This manuscript provides a systematic overview of all available historic and contemporary reports on CX injury during MV surgery, outlines recent refinements in CX injury mechanisms, describes current MV surgery associated CX injury prevention and diagnosis and treatment strategies and highlights important MV procedural aspects that may minimize the risk and consequences of CX injury.

Mechanical or biologic prostheses for mitral valve replacement: A systematic review and meta-analysis

Either a mechanical or bioprosthetic valve is used in patients undergoing mitral valve replacement (MVR). However, the optimal mitral prosthesis remains controversial. The aim of this meta‐analysis was thus to compare outcomes between mechanical mitral valve replacement (MVRm) and bioprosthetic mitral valve replacement (MVRb) for MVR patients. We searched Embase, PubMed, Web of Science, and Cochrane Library databases from January 1, 2000 to October 31, 2021 for studies that directly compared surgical outcomes of MVRm and MVRb. A total of 22 studies with 35 903 patients were included in the meta‐analysis (n = 23 868 MVRm and n = 12 035 MVRb). The MVRm group displayed lower long‐term all causes mortality (HR, 0.84; 95% confidence interval [CI]: 0.77−0.91; p < .0001; I² = 51%), and fewer mitral reoperation (hazard ratio [HR]: 0.34; 95% CI: 0.23−0.50; p < .00001; I² = 74%) than MVRb group. However, the MVRm group was associated with a greater risk of major bleeding events (HR: 1.21; 95% CI: 1.14−1.29; p < .00001; I² = 0%), stroke and systemic embolism (HR: 1.20; 95% CI: 1.10−1.32; p < .0001; I² = 0%) in matched or adjusted data. No significant difference was observed between MVRm and MVRb on operative mortality in matched/adjusted group (risk ratios: 0.83; 95% CI: 0.66−1.05; p = .12; I² = 0%). The results were consistent with patients aged under 70 years old. Patients who received a MVRm is associated with 16% lower risk of long‐term mortality and 66% lower risk of mitral reoperation, but 20% greater risk of stroke or systemic embolism, 21% greater risk of major bleeding compared with MVRb in matched/adjusted studies group, which were consistent to patients younger than the age of 70 years who underwent MVR.

Surgical mitral valve repair technique considerations based on the available evidence

Mitral valve regurgitation is the second most common valve disease in the western world. Surgery is currently the best tool for generating a long-lasting elimination of mitral valve regurgitation. However, the mitral valve apparatus is a complex anatomical and functional structure, and repair results and durability show substantial heterogeneity. This is not only due to differences in the underlying mitral valve regurgitation pathophysiology but also due to differences in repair techniques. Repair philosophies differ substantially from one surgeon to the other, and consensus for the technically best repair strategy has not been reached yet. We had previously addressed this topic by suggesting that ring sizing is "voodoo". We now review the available evidence regarding the various repair techniques described for structural and functional mitral valve regurgitation. Herein, we illustrate that for structural mitral valve regurgitation, resuspension of prolapsing valve segments or torn chordae with polytetrafluoroethylene sutures and annuloplasty can generate the most durable results paired with the best achievable hemodynamics. For functional mitral valve regurgitation, the evidence suggests that annuloplasty alone is insufficient in most cases to generate durable results, and additional subvalvular strategies are associated with improved durability and possibly improved clinical outcomes. This review addresses current strategies but also implausibilities in mitral valve repair and informs the mitral valve surgeon about the current evidence. We believe that this information may help improve outcomes in mitral valve repair as the heterogeneity of mitral valve regurgitation pathophysiology does not allow a one-size-fits-all concept.

CT Planning prior to Transcatheter Mitral Valve Replacement (TMVR)

BACKGROUND

 Transcatheter mitral valve replacement (TMVR) is a treatment option for patients with therapy refractory high-grade mitral valve regurgitation and a high perioperative risk.During TMVR, the mitral annulus cannot be visualized directly. Therefore, comprehensive pre-interventional planning and a precise visualization of the patient's specific mitral valve anatomy, outflow tract anatomy and projected anchoring of the device are necessary.Aim of this review-article is, to assess the role of pre-procedural computed tomography (CT) for TMVR-planning METHODS:  Screening and evaluation of relevant guidelines (European Society of Cardiology [ESC], American Heart Association [AHA/ACC]), meta-analyses and original research using the search terms "TVMR" or "TMVI" and "CT". In addition to this, the authors included insight from their own clinical experience.

RESULTS

 CT allows for accurate measurement of the mitral annulus with high special and adequate temporal resolution in all cardiac phases. Therefore, CT represents a valuable method for accurate prosthesis-sizing.In addition to that, CT can provide information about the valvular- and outflow-tract-anatomy, mitral valve calcifications, configuration of the papillary muscles and of the left ventricle. Additionally, the interventional access-route may concomitantly be visualized.

CONCLUSION

 CT plays, in addition to echocardiographic imaging, a central role in pre-interventional assessment prior to TMVR. Especially the precise depiction of the left ventricular outflow tract (LVOT) provides relevant additional information, which is very difficult or not possible to be acquired in their entirety with other imaging modalities.

KEY POINTS

  · CT plays a central role in pre-interventional imaging for TMVR.. · CT-measurements allow for accurate prosthesis-sizing.. · CT provides valuable information about LVOT-anatomy, mitral calcifications and interventional access-route..

CITATION FORMAT

· Heiser L, Gohmann RF, Noack T et al. CT Planning prior to Transcatheter Mitral Valve Replacement (TMVR). Fortschr Röntgenstr 2022; DOI: 10.1055/a-1718-4182.